The average weight of A , B and C is 65 kg. If the average weightof A and B is 63.5 kg and the average weight of A and C is 67.5 kg, then the weight of A ( in kg) is :
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 67
Average of A, B, and C = 65 kg
Average of A and B = 63.5 kg
Average of A and C = 67.5 kg
Sum of all observations = Average × Total number of observations
A + B + C = 65(3) = 195 kg .....(1
A + B = 63.5(2) = 127 kg ....(2
Subtracting (2) from (1), we get -
A + B + C - (A + B) = 195 - 127
C = 68 kg
A + C = 67.5(2) = 135
A + 68 = 135
A = 135 - 68 = 67 kg